This invention relates to accessory tables for wheelchairs and in particular to a wheelchair tray with an adjustable work envelope that IS controlled ergonomically and claims the benefit of priority to U.S. Provisional Application No. 60/200,814 filed Apr. 28, 2000.
Wheelchair attachments and accessories are well known. Tray tables and work envelopes support items involved in daily activities and are needed to make life easier for a seated user. Prior art patents disclose a number of tray tables beneficial to the wheelchair confined. However the prior art devices do not provide tray tables to address the needs of persons with severe impairment of hand motor skills. As illustrated in the prior art examples that follow, all existing table accessories require reaching, grasping, pulling or other movements that are not easy for persons with dexterity problems.
For almost a century, there have been inventions to provide an adjustable work surface for a seated user. In U.S. Pat. No. 723,148 issued to Dukesmith in 1903, a table design is disclosed with a fold-out shelf and writing surface. Significant manual dexterity is required of the user reaching, latching, turning, rotating and the like. Similarly, U.S. Pat. No. 1,975,034 to Poetsch discusses a table with a base and four legs having a table surface that can be tilted at several angles and used as a support surface for reading, writing, sketching, playing games, sewing and other such activities. The table surface must be lifted from a concealed position and manually adjusted upward and outward from the base.
Examples of adjustable tables specifically designed for wheelchairs are disclosed in U.S. Pat. No. 3,142,511 to Rehel disclosing a table that can be attached to a wheelchair of varying widths; U.S. Pat. No. 4,054,315 to Czemowski discussing a box-like wheelchair table with leaves that Open outward to provide an extended work surface; U.S. Pat. No. 5,228,711 to Summers covers a universal tray assembly that can fit either the right or left side of chair can be tilted; rotated and is vertically adjustable; and U.S. Pat. No. 5,454,581 to Ringer discloses a desk with an adjustable height that is attached to the wheel chair frame and can be pivoted to the side of, or in front of chair. In each instance manipulating the tray requires bending, reaching, grasping, pulling, or clamping and bolting which may be difficult actions that are even impossible for persons with limited manual dexterity or impaired hand motor control.
Thus, there is an unfilled need for an adjustable wheelchair table or work surface that is humanely engineered to meet the needs of people who would appreciate being able to easily adjust their work surface with movements that are within their ability .
The first objective of the present invention is to provide an accessory tray table for attachment to conventional wheelchairs.
The second objective of the present invention is to provide an accessory tray table wherein the work surface can be enlarged or reduced.
The third objective of the present invention is to provide an accessory tray table with a tilting mechanism that brings objects closer to or farther away from a seated user. The fourth objective of the present invention is to provide an accessory tray table that functions as a back rest capable of supporting more than one publication in an open position.
The fifth objective of the present invention is to provide an accessory tray table with a horizontal stationary base that supports the arms and upper body weight of a seated user.
The sixth objective of the present invention is to provide an accessory tray table that allows a seated user to tilt, enlarge and reduce the surface area of the work envelope with the touch of a button: foot: pedal or lever.
A preferred embodiment of the novel invention is a tray made of durable, lightweight, heat and fire-resistant material that contains a tilting mechanism and an enlarging/reducing mechanism in a compact manner, such that the operator feels in full control of the work surface, herein referred to as the xe2x80x9cwork envelope.xe2x80x9d It is to be noted that xe2x80x9cwork envelopexe2x80x9d is used interchangeably herein with xe2x80x9cmovable top portionxe2x80x9d which mayor may not include an attached auxiliary supporting rack. The controls for the tray are positioned for the convenience of the seated user and can be operated like toggle switches or joy sticks giving the user the feeling of a robot like operation thus the name for the tray disclosed herein is ROBOTRAY.
Ergo Aid is another suitable name for this novel device which is ergonomically designed because of a concern for the characteristics of people that need to be considered in arranging things that they use so that people and things will interact most effectively and safely.
Further objectives and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment which is illustrated in the accompanying drawings.